Request reconcile using patch instead of update

This should prevent the generation of the object getting bumped, as
observed on a GKE K8s 1.18 cluster using the  logic before this commit.

We only want to generation to increase when there are actual changes to
the `spec` of a resource, as some controllers use the `generation`
value to make assumptions about what they should do during a
reconciliation.

Signed-off-by: Hidde Beydals <hello@hidde.co>

cmd/flux/alert.go

@@ -37,6 +37,10 @@ func (a alertAdapter) asClientObject() client.Object {
 	return a.Alert
 }
 
+func (a alertAdapter) deepCopyClientObject() client.Object {
+	return a.Alert.DeepCopy()
+}
+
 // notificationv1.Alert
 
 type alertListAdapter struct {

cmd/flux/alert_provider.go

@@ -37,6 +37,10 @@ func (a alertProviderAdapter) asClientObject() client.Object {
 	return a.Provider
 }
 
+func (a alertProviderAdapter) deepCopyClientObject() client.Object {
+	return a.Provider.DeepCopy()
+}
+
 // notificationv1.Provider
 
 type alertProviderListAdapter struct {

cmd/flux/helmrelease.go

@@ -37,6 +37,10 @@ func (h helmReleaseAdapter) asClientObject() client.Object {
 	return h.HelmRelease
 }
 
+func (h helmReleaseAdapter) deepCopyClientObject() client.Object {
+	return h.HelmRelease.DeepCopy()
+}
+
 // helmv2.HelmReleaseList
 
 type helmReleaseListAdapter struct {

cmd/flux/image.go

@@ -42,6 +42,10 @@ func (a imageRepositoryAdapter) asClientObject() client.Object {
 	return a.ImageRepository
 }
 
+func (a imageRepositoryAdapter) deepCopyClientObject() client.Object {
+	return a.ImageRepository.DeepCopy()
+}
+
 // imagev1.ImageRepositoryList
 
 type imageRepositoryListAdapter struct {
@@ -100,6 +104,10 @@ func (a imageUpdateAutomationAdapter) asClientObject() client.Object {
 	return a.ImageUpdateAutomation
 }
 
+func (a imageUpdateAutomationAdapter) deepCopyClientObject() client.Object {
+	return a.ImageUpdateAutomation.DeepCopy()
+}
+
 // autov1.ImageUpdateAutomationList
 
 type imageUpdateAutomationListAdapter struct {

cmd/flux/kustomization.go

@@ -37,6 +37,10 @@ func (a kustomizationAdapter) asClientObject() client.Object {
 	return a.Kustomization
 }
 
+func (a kustomizationAdapter) deepCopyClientObject() client.Object {
+	return a.Kustomization.DeepCopy()
+}
+
 // kustomizev1.KustomizationList
 
 type kustomizationListAdapter struct {

cmd/flux/object.go

@@ -39,6 +39,13 @@ type adapter interface {
 	asClientObject() client.Object
 }
 
+// copyable is an interface for a wrapper or alias from which we can
+// get a deep copied client.Object, required when you e.g. want to
+// calculate a patch.
+type copyable interface {
+	deepCopyClientObject() client.Object
+}
+
 // listAdapater is the analogue to adapter, but for lists; the
 // controller runtime distinguishes between methods dealing with
 // objects and lists.

cmd/flux/receiver.go

@@ -37,6 +37,10 @@ func (a receiverAdapter) asClientObject() client.Object {
 	return a.Receiver
 }
 
+func (a receiverAdapter) deepCopyClientObject() client.Object {
+	return a.Receiver.DeepCopy()
+}
+
 // notificationv1.Receiver
 
 type receiverListAdapter struct {

cmd/flux/reconcile.go

@@ -52,6 +52,7 @@ type reconcileCommand struct {
 
 type reconcilable interface {
 	adapter     // to be able to load from the cluster
+	copyable    // to be able to calculate patches
 	suspendable // to tell if it's suspended
 
 	// these are implemented by anything embedding metav1.ObjectMeta
@@ -142,6 +143,7 @@ func requestReconciliation(ctx context.Context, kubeClient client.Client,
 		if err := kubeClient.Get(ctx, namespacedName, obj.asClientObject()); err != nil {
 			return err
 		}
+		patch := client.MergeFrom(obj.deepCopyClientObject())
 		if ann := obj.GetAnnotations(); ann == nil {
 			obj.SetAnnotations(map[string]string{
 				meta.ReconcileRequestAnnotation: time.Now().Format(time.RFC3339Nano),
@@ -150,7 +152,7 @@ func requestReconciliation(ctx context.Context, kubeClient client.Client,
 			ann[meta.ReconcileRequestAnnotation] = time.Now().Format(time.RFC3339Nano)
 			obj.SetAnnotations(ann)
 		}
-		return kubeClient.Update(ctx, obj.asClientObject())
+		return kubeClient.Patch(ctx, obj.asClientObject(), patch)
 	})
 }
 

cmd/flux/source.go

@@ -41,6 +41,10 @@ func (a bucketAdapter) asClientObject() client.Object {
 	return a.Bucket
 }
 
+func (a bucketAdapter) deepCopyClientObject() client.Object {
+	return a.Bucket.DeepCopy()
+}
+
 // sourcev1.BucketList
 
 type bucketListAdapter struct {
@@ -70,6 +74,10 @@ func (a helmChartAdapter) asClientObject() client.Object {
 	return a.HelmChart
 }
 
+func (a helmChartAdapter) deepCopyClientObject() client.Object {
+	return a.HelmChart.DeepCopy()
+}
+
 // sourcev1.HelmChartList
 
 type helmChartListAdapter struct {
@@ -99,6 +107,10 @@ func (a gitRepositoryAdapter) asClientObject() client.Object {
 	return a.GitRepository
 }
 
+func (a gitRepositoryAdapter) deepCopyClientObject() client.Object {
+	return a.GitRepository.DeepCopy()
+}
+
 // sourcev1.GitRepositoryList
 
 type gitRepositoryListAdapter struct {
@@ -128,6 +140,10 @@ func (a helmRepositoryAdapter) asClientObject() client.Object {
 	return a.HelmRepository
 }
 
+func (a helmRepositoryAdapter) deepCopyClientObject() client.Object {
+	return a.HelmRepository.DeepCopy()
+}
+
 // sourcev1.HelmRepositoryList
 
 type helmRepositoryListAdapter struct {